Locking systems of the dead bolt type are in current use on doors especially in houses. A key is needed to unlock the locking system and a thumb member is located on the inside to operate the locking system. This is required because of local code requirements to enable a person to unlock the door from the inside in case of an emergency, such as a fire.
Security doors are being added to existing houses to prevent them from being burglarized and these doors also function as storm doors and screen doors. A dead bolt lock with a thumb member on the inside is not acceptable because the glass in the storm door or the screen in the screen door can be broken or torn enabling a person who wants to break into the house to operate the thumb member and unlock the dead bolt lock and gain access to the house.